We propose to develop an inexpensive, handheld device that can be used by primary caregivers (such as general practitioners, internists, and endocrinologist) and in screening settings to reliably screen at-risk diabetics for retinopathy. This device has the potential to save the sight of thousands of diabetics who have undetected diabetic retinopathy by identifying their condition and allowing timely referral to an ophthalmologist for evaluation treatment. The device works by measuring the implicit time of the 30 Hz flicker electroretinogram, which has been repeatedly shown to correlate well with severity of diabetic retinopathy. Because the device measures implicit time, it will record from skin electrodes that touch the skin near the eyes. The device will automatically detect good electrode contact. Pupil size will be automatically measured and the light intensity will be adjusted to provide an optimal retinal illuminance. Proven algorithms will be used to measure the implicit time from the elicited waveform, and the results will be displayed to the caregiver along with and estimate of the reliability of the measurement. LKC Technologies already possesses most of the technologies necessary to develop this device, notably compact low noise, saturation-resistant digital patient amplifiers, sophisticated circuitry for controlling the light output of LEDs, and proven analysis algorithms. In Phase I, we propose to develop and evaluate a proof-of-principle prototype by modifying and LKC visual electrophysiology system with an off-the shelf pupillometer and custom software. We will record data from diabetic patients using skin electrodes to assess the robustness of the algorithms for measuring signal quality and extracting implicit time and to determine optimal stimulus parameters. In Phase II, a complete prototype instrument would be constructed, and data will be collected from an extensive population of diabetics with retinopathy to demonstrate the effectiveness of the device. PUBLIC HEALTH RELEVANCE Fifteen million people in the United States suffer from diabetes; five million of them have some degree of diabetic retinopathy - the leading cause of blindness in working age adults. Although $493 million is expended annually for healthcare related to diabetic retinopathy, another 20,000 people in the United States will go blind this year from the disease. Many diabetics do not know that they have diabetic retinopathy because there is no quick, easy, inexpensive, and widely available screening method. This project proposes to develop a compact, easy-to-use, cost-effective device that would allow diabetics at risk for retinopathy to be evaluated quickly and inexpensively in primary care or screening environments and referred for treatment to preserve their sight. [unreadable] [unreadable] [unreadable]